1. Field
The present disclosed subject matter relates to a semiconductor composite device and method of manufacturing the same. More particularly, it relates to a composite semiconductor device including a plurality of light emitting units on the same substrate and method of manufacturing the same.
2. Description of the Related Art
There have been proposed semiconductor light emitting sources which include a plurality of light emitting units with respective different emission spectra and which are formed on the same substrate composed of a semiconductor material or on the same device. These conventional are devices are described as follows: (1) a semiconductor composite light emitting device which includes semiconductor crystal layers having a plurality of active layers (light emitting layers) with different respective emission spectra that are sequentially grown on the same substrate (see, for example, Patent Document 1: JP Patent No. 3298390); (2) an LED display which includes semiconductor crystal layers having light emitting layers with different respective emission spectra that are sequentially or simultaneously grown on the same substrate (see, for example, Patent Document 2: JP 2004-79933A); (3) a semiconductor light emitting device which includes a GaN-based LED mounted facedown on an Si diode via micro-bumps (see, for example, Patent Document 3: WO 98/34285); and (4) a full-color semiconductor light emitting device which includes semiconductor light emitting devices of the flip-chip type that are operative to emit red, green and blue lights and which are mounted on an Si diode via micro-bumps (see, for example, Patent Document 4: JP 11-307818A).
In the above-listed conventional art document (1), an increase in the number of the light emitting layers extensively increases the steps in the epitaxial growth process. This results in an elongated lead-time, with a lowered producibility and an increased production cost, and also makes it difficult to insure excellent reproducibility on respective growth conditions in all growth processes. Therefore, the light emitting layers cause variations in emission spectra and thus the exit light from the resultant composite semiconductor light emitting device exhibits a large variation in color tone, which makes it difficult to control color tone.
In the above-listed conventional art document (2), the composition ratio and growth temperature associated with the compound semiconductor may be controlled to form the light emitting layers having a plurality of desired emission spectra selectively in order or at the same time. In this case, a highly precise execution of selective composition control and temperature control are required for growth regions for use in formation of the light emitting layers therein, which also requires the use of high technology products and methods. Therefore, it is difficult for this method to be used to realize an LED display with less variation in color tone.
In the above-listed conventional art document (3), if the LED mounted on the Si diode has an upper electrode that is wire bonded, the heat, pressure and vibrations on the wire bonding apply a stress on the micro-bumps that connect the Si diode with the LED. This stress impairs the reliability of the connection strength and electrical properties. Therefore, the LED is limited to one that has a structure capable of facedown mounting, which restricts the flexibility of LED selection. In addition, suppression of the load imposed on the LED and the Si diode on mounting the LED requires a certain restriction on the mount condition. In this case, the bonding strength between devices may become lower to possibly deteriorate the reliability of the device.
In the above-listed conventional art document (4), the semiconductor light emitting devices are mounted independently. Therefore, the interval between adjacent devices is extended which can deteriorate the color mixture properties of the device.